Investigation of an outbreak of diphtheria in Borborooah block of Dibrugarh district, Assam

Abstract

Diphtheria is a highly contagious and potentially life threatening bacterial disease caused by corynebacterium diphtheria.(1) The EPI of WHO recommends three doses of DPT vaccine starting at six weeks of age with additional doses of diphtheria vaccine in countries where resources permit. Many national immunization programs, including the UIP in India offer two booster doses at 18 months and between 54 to 72 months of age; after three doses of primary vaccines, protective levels of antitoxin develop in 94–100% of the children. However without booster doses, over time toxoid induced antibody drops below protective level.(2) In 2008, India contributed 6081(86.66%) of the 7017 diphtheria cases reported globally.(3) There were no reports of outbreaks of diphtheria in Assam since last few years, though sporadic cases were reported in UIP monthly report, which were never investigated and documented. The number of cases coming to Assam Medical College was very few and the immunization coverage in Assam was 19.30% in 2006(RHS), which has improved to 67.60% in 2006–2007. In Dibrugarh District of Assam in 2008–2009, administrative data shows coverage of 90%, while the evaluated data from Regional Resource Centre shows coverage of 78%. As outbreak of diphtheria reflects the impact of immunization outbreak investigation was carried out to assess the diphtheria outbreak pattern and case fatality rate in Borborooah block of Dibrugarh district of Assam.